In order to automate the manual work performed in the removal of broken threads and in the presentation of the thread in spinning, twisting or winding frames, service carriages are known that travel along the sides of the frame. The carriage may for example be one which is provided with a knotter (see German Patent No. 2,035,025). However, service carriages have already been proposed that permit the automatic presentation of a thread, i.e. which draw the thread from the supply bobbin, through the various parts of the frame and present it to the take-up bobbin. Although these service carriages have an electrical drive for moving them along the side of the frame and also other electrically moved parts, these service carriages also include a plurality of pneumatically driven devices. For picking up and conveying the thread suction nozzles, blower nozzles and injectors are provided. Furthermore, compressed air cylinders are provided for moving the various parts. Also, the suction effect at the suction nozzles is often created by injectors or the like driven by compressed air, so that such a service carriage has a high consumption of compressed air.
In principle, it should be possible to generate the compressed air by means of a compressor arranged in the frame and driven by an electric motor. However, in order that the large quantity of compressed air required for rapid operation of the service carriage may be available at all times, there must be provided on the carriage, in addition to the compressor, a compressed air reservoir of large volume. This compressor and its associated compressed air reservoir, however, greatly increase the weight of the service carriage. This increase in weight conflicts with the efforts made to keep the service carriage as small as possible in order that it may be rapidly accelerated and stopped and that the guide rails that it requires may be of as light construction as possible. Also, in most cases there is insufficient space on the service carriage for a large compressor with its compressed air reservoir, since the carriage already contains a large number of other devices. In a service carriage in which the suction effect is created by only one suction blower (see German Patent No. 1,685,932) difficulties likewise occur owing to the space required by a sufficiently powerful blower and its weight.
In the case of a compressed air supply arrangement of the type mentioned initially it is therefore already known (see German Auslegeschrift 2,360,084) to provide a stationary source of compressed air, i.e., a compressor, and to feed the compressed air to the service carriage via a flexible hose which is dragged along by the carriage. This hose may be connected either to the compressed air mains that are provided in many factories, or to a stationary compressor arranged on the frame. A hose which is dragged along and is under pressure is however subjected to continuous flexing and hence to rapid wear. Furthermore, an automatically winding hose reel must be provided. In spite of this precaution the service carriage was able to move along only one frame, and always had to be moved back to its starting position by a return movement. Such a to and fro movement has the disadvantage, however, that the service carriage, in the vicinity of its point of reversal, again passes, after a relatively short time, the spindles that have already been serviced or inspected, whilst it takes a relatively long time before it again reaches the spindles at the other point of reversal. A circulatory movement of the service carriage in one direction would be preferable in this connection.
The invention is based on the problem of providing a compressed air supply arrangement for a service carriage of the type referred to initially, which whilst avoiding the above-mentioned disadvantages permits the supply of compressed air to one or more service carriages, the service carriage or carriages being capable of travelling along one or more frames independently of the compressed air supply, and the compressed air supply arrangement itself requiring only very little space on the carriage.
In accordance with the invention this is achieved by arranging on each side of the frame a stationary compressed air duct extending in the direction of the frame and connected to the compressed air source, the duct having a plurality of automatically closing button-actuated valves, by arranging for the spacing of the valves to correspond to spindle distribution or a whole multiple thereof, and by providing on the service carriage at least one coupling head which is movable transversely to the direction of movement of the carriage and which is provided with an opening member which when firmly applied to the valve opens it, the coupling head being connected to the compressed air system of the service carriage.
Since with this novel compressed air supply arrangement the source of compressed air is provided externally of the service carriage, the carriage is not substantially loaded by the compressed air supply arrangement, and the compressed air supply arrangement requires only a minimum space on the carriage. The necessary compressed air may be generated by a stationary compressor arranged in one of the spinning, twisting or winding frames, or it may be taken from a compressed air supply main already present. Such a stationary compressor may be of sufficiently large construction to generate the required quantity of compressed air. In a central compressed air supply main a large quantity of compressed air is available. During the movement of the service carriage along the frame this is separated from the stationary compressed air duct. Only when the carriage has come to a standstill at a spindle to be serviced is a connection made between the coupling head which is movable on the carriage and the appropriate valve. The service carriage, since it is not connected to a hose to be dragged along, can therefore move in any desired direction, even along both sides of a frame or along the sides of a plurality of frames. Also, with the novel compressed air supply arrangement a plurality of service carriages may be supplied at the same time, if this is necessary.
Advantageously, there are provided on the service carriage a plurality of coupling heads arranged one behind the other in the direction of movement of the carriage, their spacing corresponding to the spindle distribution, the spacing of the valves being greater by one spindle spacing than the spacing of the two outer coupling heads from one another. In this manner the number of valves is reduced, without it being necessary to increase the number of coupling heads to the same extent as the number of valves is reduced. Thus for example it is advantageous if plug valves are provided only at each fourth spindle and the service carriage has four coupling heads arranged one behind the other at the same spacing as the spindle distribution. It is immaterial which of the four spindles has to be serviced and in front of which the service carriage therefore comes to a standstill. One of the coupling heads always registers with a valve provided at the four spindles and establishes communication with the compressed air duct located in the frame.